Traffic congestion is becoming an increasing concern. Traffic congestion typically results from increased use of the roads by vehicles, and is characterized by slower vehicle speeds, longer trip times, and increased vehicular queuing. Traffic signals have been widely deployed in an attempt to help alleviate traffic congestion. Proper functioning traffic signals need to not only ensure that traffic moves smoothly and safely, but that pedestrians are protected when crossing the roads.
Various traffic signal control techniques have been proposed. These techniques can be generally categorized as fixed time control, dynamic control, coordinated control, and adaptive control. Fixed time control is rather simple in that traffic signals are changed after a fixed time period. The time period can be pre-configured to different values for different times in a day. Dynamic control incorporates the use of input from detectors, such as sensors, to adjust the traffic signal timing. These detectors can inform the traffic signal controller whether vehicles are present.
Coordinated control is coordinated control of multiple traffic signals, typically by a master controller, which accounts for changing traffic patterns in real-time. Cameras and sensors are used to detect real-time traffic information, and the central controller uses this information to do real-time optimization. One optimization is a “green wave,” which is a long string of green lights that allows vehicles to travel long distances without encountering a red light.
Adaptive control incorporates actual traffic demand in the control of traffic signals. Sensors and cameras are used to determine the number of vehicles at an intersection and how long the vehicles have been waiting. The traffic signal controller at this intersection uses this information to control the traffic signal at this intersection, while coordinating its decision with controllers at other intersections.
The subject matter claimed in the present disclosure is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one example technology area where some embodiments described in the present disclosure may be practiced.